Piezoelectric driving-charge modulation high-precision ink droplet jet printing device

Abstract

The utility model relates to the technical field of ink-jet printing, in particular to a piezoelectric driving-charge modulation high-precision ink droplet jet printing device, which comprises a nozzle main body, a charge modulation system, a piezoelectric driving circuit and an ink supply system. The nozzle body is composed of an ink jet box and a piezoelectric driving device, an ink guide cavity is formed in the ink jet box, a plurality of nozzles communicated with the ink guide cavity are arranged at the bottom of the ink jet box, the piezoelectric driving device composed of a piezoelectric ceramic tube and a glass capillary tube is arranged in each nozzle, and accurate ink droplet generation is achieved through high-voltage pulse control. The charge modulation system comprises an annular electrode surrounding an outlet of the nozzle and a high-voltage power supply and is used for applying a controllable electrostatic field to sprayed ink droplets and adjusting the flight path of the ink droplets, and the control system comprises a waveform controller, a pulse generator and a sub-controller and is used for realizing synchronous control of a driving signal and charge modulation. The ink supply system is composed of an ink storage box, a micro peristaltic pump and a pressure sensor, and stable ink supply is ensured.

Description

Technical Field

[0001] This utility model relates to the field of inkjet printing technology, specifically a piezoelectric-driven, charge-modulated high-precision ink droplet printing device. Background Technology

[0002] In the fields of modern precision manufacturing and micro-nano fabrication, inkjet printing technology is widely used in various high-tech areas such as flexible electronics, biochips, optical devices, and 3D printing due to its advantages such as non-contact operation, high material utilization, and patternable control. Currently, the mainstream inkjet printing methods mainly include two types: thermal inkjet and traditional piezoelectric ceramic inkjet.

[0003] Among them, thermal printheads generate bubbles by heating ink to propel ink droplets out, but this method has problems such as ink composition deterioration due to heating, easy clogging of nozzles, and short service life, which limits its application in the field of functional inks (such as conductive inks and nano inks); while conventional piezoelectric ceramic printheads avoid heating problems and have the advantages of fast response speed and long service life, they still have certain limitations in terms of ink droplet volume control accuracy and spray direction consistency, making it difficult to meet the growing demand for high-resolution and high-stability printing.

[0004] Furthermore, most existing inkjet systems rely on a single mechanical or electrothermal drive method, lacking effective means to control the trajectory of ink droplets. This results in insufficient adaptability when dealing with complex graphic printing, multi-material co-printing, and high-speed motion platform matching. Especially when using high-viscosity, low-surface-tension, or electrically sensitive inks, problems such as droplet deviation, inaccurate landing, and splattering can easily occur, affecting the final print quality. Utility Model Content

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this invention provides a high-precision ink droplet printing device driven by piezoelectric charge modulation.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, this utility model provides the following technical solution: A piezoelectric-driven, charge-modulated high-precision ink droplet printing device of this utility model, comprising:

[0009] The printhead body includes an inkjet cartridge and a piezoelectric drive device. The inkjet cartridge has an ink guiding cavity inside, and a plurality of nozzles are provided at the bottom of the inkjet cartridge. The nozzles are connected to the ink guiding cavity, and the piezoelectric drive device is disposed inside the nozzles.

[0010] A charge modulation system includes a ring electrode and a high-voltage power supply, the ring electrode being surrounded at the nozzle outlet and connected to the high-voltage power supply;

[0011] The piezoelectric drive circuit includes a pulse generator and a waveform controller, used to generate high-voltage pulse signals to drive the piezoelectric drive device;

[0012] The ink supply system includes an ink reservoir, a miniature peristaltic pump, and a pressure sensor.

[0013] Preferably, the piezoelectric drive device includes a piezoelectric ceramic tube and a glass capillary tube, wherein the piezoelectric ceramic tube is wrapped around the outside of the glass capillary tube, and the piezoelectric ceramic tube is provided with electrical terminals.

[0014] More preferably, the high-voltage power supply is installed at the end of the inkjet cartridge, and the high-voltage power supply is equipped with a sub-controller, which is electrically connected to the high-voltage power supply, the waveform controller, and the ring electrode.

[0015] Preferably, the waveform controller is electrically connected to the pulse generator, and the pulse generator is connected to the power terminal of the piezoelectric ceramic tube.

[0016] Preferably, it includes a charge sensor, which is electrically connected to a ring electrode.

[0017] More preferably, the pressure sensor is installed inside the inkjet cartridge, and the miniature peristaltic pump is connected to the ink reservoir and the ink guide cavity via a pipe.

[0018] Preferably, the nozzle has a tapered inner wall structure.

[0019] Preferably, the inner wall of the nozzle is coated with a diamond-like carbon coating, and the surface of the annular electrode is coated with a platinum layer.

[0020] (III) Beneficial Effects

[0021] Compared with the prior art, this utility model provides a high-precision ink droplet printing device driven by piezoelectric charge modulation, which has the following advantages:

[0022] The printhead body adopts an ink cartridge and ink guide cavity structure, which, together with the bottom multi-hole nozzle, achieves stable ink supply; the piezoelectric drive device consists of a piezoelectric ceramic tube and a glass capillary tube, which can generate controllable deformation under an applied high-voltage pulse to achieve high-resolution ink droplet ejection; the optimized tapered nozzle inner wall structure helps to improve the consistency of ink droplet formation and reduce satellite droplet phenomenon; the inner wall of the nozzle is coated with a diamond-like carbon coating to enhance wear resistance and chemical stability and extend service life.

[0023] The charge modulation system, consisting of a ring electrode and a high-voltage power supply, is positioned at the nozzle exit. It applies a directional electrostatic field to the ink droplets after they are ejected, thereby controlling their flight trajectory. The ring electrode is plated with a platinum layer, improving conductivity and corrosion resistance, ensuring long-term stability of the charge modulation. A further optimized charge sensor provides real-time feedback on the ink droplet charge, enabling closed-loop control and improving printing accuracy.

[0024] In terms of the control system, the waveform controller and pulse generator work together to precisely adjust the drive signal and improve the accuracy of ink droplet volume control. In the ink supply system, the miniature peristaltic pump works with the ink storage box and pressure sensor to ensure continuous ink supply and prevent clogging. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0026] Figure 2 This is a bottom view of the inkjet cartridge structure of this utility model;

[0027] Figure 3 This is a schematic diagram of the cross-sectional structure of the inkjet cartridge of this utility model;

[0028] In the diagram: 1. Inkjet cartridge; 2. Ink reservoir; 3. Ink guide chamber; 4. Nozzle; 5. Glass capillary tube; 6. Piezoelectric ceramic tube; 7. Electrical terminal; 8. Ring electrode; 9. High voltage power supply; 10. Controller; 11. Waveform controller; 12. Pulse generator; 13. Pressure sensor; 14. Miniature peristaltic pump. Detailed Implementation

[0029] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0030] Please see Figure 1-3 This utility model discloses a piezoelectric-driven, charge-modulated high-precision ink droplet printing device, comprising:

[0031] The printhead body includes an inkjet cartridge 1 and a piezoelectric drive device. The inkjet cartridge 1 is provided with an ink guiding cavity 3. The bottom of the inkjet cartridge 1 is provided with a plurality of nozzles 4. The nozzles 4 are connected to the ink guiding cavity 3. The piezoelectric drive device is disposed in the nozzles 4.

[0032] A charge modulation system includes an annular electrode 8 and a high-voltage power supply 9, wherein the annular electrode 8 surrounds the outlet of the nozzle 4 and is connected to the high-voltage power supply 9;

[0033] The piezoelectric drive circuit includes a pulse generator 12 and a waveform controller 11, used to generate a high-voltage pulse signal to drive the piezoelectric drive device;

[0034] The ink supply system includes an ink reservoir 2, a micro peristaltic pump 14, and a pressure sensor 13.

[0035] This invention proposes a high-precision ink droplet printing device driven by piezoelectric charge modulation. Its core lies in generating ink droplets through the mechanical deformation of piezoelectric ceramics and controlling the trajectory of the ink droplets through a charge modulation system, thereby achieving precise control of both the volume and landing position of the ink droplets.

[0036] The device mainly consists of the following functional modules:

[0037] Printhead body: includes ink cartridge 1 and piezoelectric drive device, used to store ink and drive ink droplets to be ejected;

[0038] Charge modulation system: A controllable electrostatic field is applied at the nozzle 4 outlet to adjust the ink droplet flight path;

[0039] Piezoelectric drive circuit: generates high-voltage pulse signals to drive the piezoelectric ceramic to deform in order to control the size and frequency of ink droplets;

[0040] Ink supply system: Ensures stable ink supply, improving printing continuity and stability;

[0041] Detailed Explanation of the Working Principles of Each Optimized Technical Solution

[0042] nozzle body structure

[0043] Inkjet cartridge 1 + ink guide chamber 3 + nozzle 4 structure:

[0044] The ink is stored in the inkjet cartridge 1 and delivered to the nozzle 4 through the ink guide cavity 3;

[0045] The number of nozzles 4 can be a multi-hole array to meet the needs of high-speed printing.

[0046] Piezoelectric drive device (piezoelectric ceramic tube 6 + glass capillary tube 5):

[0047] The piezoelectric ceramic tube 6 encloses the glass capillary tube 5. When a high-voltage pulse is applied, the piezoelectric ceramic deforms, squeezing the ink cavity inside the capillary tube to form ink droplet ejection.

[0048] Terminal 7 is used to connect to an external drive circuit to ensure accurate voltage input.

[0049] Charge modulation system

[0050] Ring electrode 8 + high voltage power supply 9:

[0051] The annular electrode 8 surrounds the nozzle 4 outlet, forming a uniform electrostatic field;

[0052] The high-voltage power supply 9 provides an adjustable voltage, which causes the ink droplets to carry a controllable charge after leaving the nozzle 4, and deflect them in the electric field.

[0053] The sub-controller 10 coordinates the high-voltage power supply 9 and the waveform controller 11 to achieve synchronous control of charge and ink droplet ejection.

[0054] The sub-controller 10 achieves precise control of the output voltage through the following methods:

[0055] Digital signal processor (DSP) or microcontroller (MCU)

[0056] Principle: The sub-controller 10 is usually equipped with a high-performance digital signal processor (DSP) or microcontroller (MCU). These chips can execute complex algorithms to calculate the required voltage value and generate the corresponding control signal.

[0057] Function: Based on instructions from the control system (such as waveform controller 11, pulse generator 12, etc.), the DSP or MCU processes the data and generates PWM (pulse width modulation) signals or other forms of control signals to precisely adjust the output voltage.

[0058] Pulse Width Modulation (PWM) Technology

[0059] Principle: PWM is a technique that regulates average voltage by changing the duty cycle of a signal. The sub-controller 10 can use the PWM signal to control the switching state of the high-voltage power supply 9, thereby regulating the output voltage.

[0060] Function: By adjusting the duty cycle of the PWM signal, the effective voltage value applied to the ring electrode 8 can be changed without altering the power supply frequency. This method features fast response and high accuracy.

[0061] Variable resistor or digital potentiometer

[0062] Principle: Some controllers 10 may use variable resistors or digital potentiometers as voltage regulation elements. These elements can be remotely controlled by electronic signals to change their resistance values, thereby affecting the voltage distribution in the circuit.

[0063] Function: When it is necessary to change the output voltage, the system will send a command to the digital potentiometer to adjust its resistance value, thereby changing the voltage division ratio and achieving the purpose of regulating the output voltage.

[0064] Feedback loop and closed-loop control

[0065] Principle: To ensure the stability of the output voltage, the sub-controller 10 typically includes a feedback loop. This loop monitors the actual output voltage in real time and compares it with a preset target voltage.

[0066] Function: If a deviation is detected, the feedback loop will automatically adjust the control signal to bring the output voltage back to the set value. This closed-loop control system can effectively compensate for voltage fluctuations caused by load changes or other external factors.

[0067] Isolation transformer or DC-DC converter

[0068] Principle: In some designs, the controller 10 may utilize an isolation transformer or a DC-DC converter to achieve voltage conversion and isolation functions. These devices can adjust the output voltage according to the proportional relationship of the input signal.

[0069] Function: They not only provide electrical isolation, but also enable efficient conversion from high voltage to low voltage or vice versa, ensuring that the output voltage meets requirements.

[0070] piezoelectric drive circuit

[0071] Pulse generator 12 + waveform controller 11:

[0072] Pulse generator 12 outputs a voltage waveform of a specific shape;

[0073] Waveform controller 11 adjusts waveform parameters according to the required droplet size and frequency;

[0074] The control signal is ultimately transmitted to the piezoelectric ceramic tube 6 through the power terminal 7, driving its deformation.

[0075] Ink supply system

[0076] Ink cartridge 2 + miniature peristaltic pump 14 + pressure sensor 13:

[0077] Ink cartridge 2 stores ink;

[0078] The miniature peristaltic pump 14 delivers ink through the pipe to the ink guide chamber 3;

[0079] Pressure sensor 13 monitors the pressure in ink delivery chamber 3 to prevent clogging or insufficient ink supply.

[0080] Technical Functions of Each Preferred Structure

[0081] The tapered nozzle 4 reduces ink flow resistance, enhances droplet formation consistency, and reduces satellite droplets.

[0082] Diamond-like carbon coating improves nozzle abrasion resistance and chemical stability, extending service life, and is especially suitable for corrosive inks.

[0083] The platinum layer electrode surface enhances the electrode's conductivity and corrosion resistance, ensuring the long-term stable operation of the charge modulation system.

[0084] The charge sensor detects the charge on the ink droplets in real time and feeds it back to the control system to achieve closed-loop adjustment and improve printing accuracy.

[0085] Charge sensors can be applied using relevant equipment with mature technologies, such as the FMX-004Static Locato series and ME300 Series charge detection equipment.

[0086] Detailed Workflow Summary

[0087] Step S1: Startup Preparation

[0088] When the device is turned on, ink is fed from the ink reservoir 2 into the ink delivery chamber 3 by the micro peristaltic pump 14;

[0089] Pressure sensor 13 monitors ink pressure in real time to ensure stable ink supply.

[0090] Step S2: Piezoelectric-driven droplet generation

[0091] The waveform controller 11 sets the inkjet parameters (such as droplet size and frequency) and sends the command to the pulse generator 12;

[0092] Pulse generator 12 generates a high-voltage pulse signal and transmits it to piezoelectric ceramic tube 6;

[0093] When the piezoelectric ceramic tube 6 is excited, it undergoes periodic contraction / expansion, squeezing the ink cavity in the glass capillary tube 5 and forcing the ink droplets to be ejected from the nozzle 4.

[0094] Step S3: Charge Modulation of Ink Droplet Trajectory

[0095] The high-voltage power supply 9 applies a controllable voltage to the ring electrode 8 through the sub-controller 10, forming a directional electrostatic field;

[0096] When the ejected ink droplets pass through the electrode area, they acquire a controllable charge and are deflected in the electric field;

[0097] A charge sensor provides feedback on the actual charge of the ink droplet, and the control system dynamically adjusts the voltage to achieve trajectory correction.

[0098] Step S4: Monitoring and Adjustment of the Printing Process

[0099] Pressure sensor 13 continuously monitors the ink flow status;

[0100] If an abnormality occurs (such as a drop in pressure), the system will automatically alarm or switch to a backup ink path;

[0101] The charge sensor works in conjunction with the waveform controller 11 to ensure consistency in each inkjet print.

[0102] Step S5: Complete printing

[0103] The ink droplets fall accurately onto the target substrate according to the preset pattern;

[0104] The equipment will automatically clean itself or enter standby mode to prepare for the next round of operations.

[0105] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A piezoelectric-driven, charge-modulated high-precision ink droplet printing device, characterized in that, include: The printhead body includes an inkjet cartridge (1) and a piezoelectric drive device. The inkjet cartridge (1) is provided with an ink guiding cavity (3). The bottom of the inkjet cartridge (1) is provided with a plurality of nozzles (4). The nozzles (4) are connected to the ink guiding cavity (3). The piezoelectric drive device is disposed in the nozzles (4). The charge modulation system includes a ring electrode (8) and a high-voltage power supply (9), the ring electrode (8) surrounding the nozzle (4) outlet and connected to the high-voltage power supply (9); The piezoelectric drive circuit includes a pulse generator (12) and a waveform controller (11) for generating high-voltage pulse signals to drive the piezoelectric drive device; The ink supply system includes an ink reservoir (2), a micro peristaltic pump (14), and a pressure sensor (13).

2. The piezoelectric-driven, charge-modulated high-precision ink droplet printing device according to claim 1, characterized in that, The piezoelectric drive device includes a piezoelectric ceramic tube (6) and a glass capillary tube (5). The piezoelectric ceramic tube (6) is wrapped around the outside of the glass capillary tube (5), and the piezoelectric ceramic tube (6) is provided with a power terminal (7).

3. The piezoelectric-driven, charge-modulated high-precision ink droplet printing device according to claim 1, characterized in that, The high-voltage power supply (9) is installed at the end of the inkjet cartridge (1). The high-voltage power supply (9) is equipped with a sub-controller (10), which is electrically connected to the high-voltage power supply (9), the waveform controller (11), and the ring electrode (8).

4. The piezoelectric-driven, charge-modulated high-precision ink droplet printing device according to claim 2, characterized in that, The waveform controller (11) is electrically connected to the pulse generator (12), and the pulse generator (12) is connected to the power terminal (7) of the piezoelectric ceramic tube (6).

5. The piezoelectric-driven, charge-modulated high-precision ink droplet printing device according to claim 1, characterized in that, Includes a charge sensor, which is electrically connected to a ring electrode (8).

6. The piezoelectric-driven, charge-modulated high-precision ink droplet printing device according to claim 1, characterized in that, The pressure sensor is installed inside the inkjet cartridge (1), and the micro peristaltic pump (14) is connected to the ink reservoir (2) and the ink guide cavity (3) through a pipe.

7. The piezoelectric-driven, charge-modulated high-precision ink droplet printing device according to claim 1, characterized in that, The nozzle (4) adopts a tapered inner wall structure.

8. The piezoelectric-driven, charge-modulated high-precision ink droplet printing device according to claim 1, characterized in that, The inner wall of the nozzle (4) is coated with a diamond-like carbon coating, and the surface of the annular electrode (8) is coated with a platinum layer.

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